Firth developed a particular view of linguistics that has given rise to the adjective 'Firthian'. Central to this view is the idea of polysystematism. David Crystal describes this as:

an approach to linguistic analysis based on the view that language patterns cannot be accounted for in terms of a single system of analytic principles and categories ... but that different systems may need to be set up at different places within a given level of description.

As a teacher in the University of London for more than 20 years, Firth influenced a generation of British linguists. The popularity of his ideas among contemporaries gave rise to what was known as the 'London School' of linguistics. Among Firth's students, the so-called neo-Firthians were exemplified by Michael Halliday, who was Professor of General Linguistics in the University of London from 1965 until 1987.

Firth encouraged a number of his students, who later became well known linguists, to carry out research on a number of African and Oriental languages. T. F. Mitchell worked on Arabic and Berber, Frank R. Palmer on Ethiopean languages, including Tigre, and Michael Halliday on Chinese. Some other students whose native tongues were not English also worked with him and that enriched Firth's theory on prosodic analysis. Among his influential students were the Arab linguists Ibrahim Anis and Tammam Hassanand Kamal Bashir . Firth got many insights from work done by his students in Semitic and Oriental languages so he made a great departure from the linear analysis of phonology and morphology to a more of syntagmatic and paradigmatic analysis, where it is important to distinguish between the two levels of phonematic units (equivalent to phone (phonetics)) and prosodies (equivalent to features like "nasalization", "velarization" etc.). Prosodic analysis paved the way to autosegmental phonology, though many linguists, who do not have a good background on the history of phonology, do not acknowledge.[6]